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Physiology of Sleep and Dreams :

Physiology of Sleep and Dreams

Nature of Sleep and Dreams :

Nature of Sleep and Dreams Sleep and dreams as biological rhythms
When do people sleep, if they don’t have a clock?
Sleep and dreams as physiological states
What parts of the brain are active and what parts are inactive during sleep and dreaming
Sleep and dreams as drives/instincts
What is the purpose of sleep or dreams?

Biological Rhythms :

Circadian Rhythms :

Circadian Rhythms Humans, like all mammals, have a 24 hour biological “clock”
If people are placed in an environment without any access to daylight, to clocks, or to other markers of time, they follow an activity/rest cycle of about 24.5 hours
Shown by Nathaniel Kleitman in a study in Mammoth Cave, Kentucky

Genetics of Biological Clocks :

Genetics of Biological Clocks Multiple genes are known to be involved in the clock
per (period)
tim (timeless)
per and tim both have circadian rhythms
enter nucleus at night and shut off clock
clock
starts production of per and tim in nucleus

Entrainment :

Entrainment A zeitgeber or timing signal, can reset the clock
Sunrise is one signal
Changing the time of day of the signal can alter the timing of the biological process

Nathaniel Kleitman (1895-1999) :

Control of Cycles :

Control of Cycles Sleep/wake cycle and the suprachiasmatic nucleus (SCN)
lesions of SCN eliminate sleep/waking cycle
REM/NREM cycle and the pontine reticular formation

SCN Control of Circadian Rhythm :

SCN Control of Circadian Rhythm

The Cycles of Sleep Stages :

The Cycles of Sleep Stages

Control of REM by Pontine Nuclei :

Control of REM by Pontine Nuclei

The Description of Brain Waves :

The Description of Brain Waves Two parameters
frequency
the number of waves per second, measured as Hertz, Hz
amplitude
the height of waves, measured in EEG recordings as microvolts, or V
Synchronization
synchronized: waves are aligned with each other in time
desynchronized: waves occur randomly with each other in time

Brain Circuits in Narcolepsy :

Brain Circuits in Narcolepsy

New Ideas on Narcolepsy :

New Ideas on Narcolepsy Animal models
Doberman pinschers
Neurochemical Basis
Defect in Hypocretins or Orexins (HO)
Narcoleptic people have little HO
Genetic basis
Defective gene found in dogs
No genetic abnormality in people